2 BULLETIN 1229, U. S. DEPARTMENT OF AGRICULTURE. 
occur on leaves, stolons, and flower pedicels, and even in the flowers 
and fruits themselves. In the leaves the swellings may be in the peti- 
oles, either basally. intermediate, or involving the blade. They vary 
greatly in size, but are often several times the diameter of the leaf 
stem. The gall on the petiole is spindle shaped as a rule and often 
an inch or more in length. The swellings in the leaf blades are 
characteristically crinkled thickenings of greater or less extent, 
sometimes but not always made more prominent by a reddening 
against the green background. The leaf symptoms are not likely 
to be confused with those of any other disease. 
The stolon symptoms are like those on the petioles. A swelling 
may be anywhere on the stolon, even on its tip. (PL I. B.) This un- 
doubtedly is a factor in its distribution, the new plant in this case 
being affected at the outset. Fruiting stems are sometimes badly 
affected. Usually the galls occur most prominently as long club- 
shaped swellings just below the blossoms. Often the parts of the 
calyx or even the petals and receptacle are greatly enlarged and 
distorted. Fruits in all stages of maturity are sometimes irregu- 
larly swollen. 
In Hypochaeris the symptoms as seen in the summer and fall con- 
sist mainly of swellings in the leaves, as they lie in a rosette on the 
ground. They are often distorted and twisted abnormally, especially 
when the gall is in the midrib. (PL II.) Here, as in the strawberry, 
a reddish coloration is sometimes evident on the leaves, but this is 
not the rule. Evidences of typical galls in flower steins were found 
as well, in the form of slight increases in thickness at their bases. 
Stem galls produced by an insect (Aulax hypockoeridis Kieff) were 
observed quite frequently also and should not be confused with the 
nematode swellings. The insect galls as a rule are much larger and 
more spongy in texture than those produced by the nematodes. 
Thanks are due to Dr. E. P. Felt, New York State, entomologist, 
and to L. H. Weld, of the Smithsonian Institution. Washington, 
D. C, for identification of the insect. 
THE CAUSAL ORGANISM. 
Examination of the typical swellings and galls invariably disclosed 
the presence in them of Tylenchus. Those from the strawberry had 
already been authentically identified as Tylenchus dipsaci. The Hy- 
pochaeris nematode appeared identical in every way with that found 
in alfalfa, clover, and strawberry and was so determined. Our iden- 
tification was later verified by Dr. N. A. Cobb, nematologist. at 
Washington. D. C, who reported only a slight and insignificant va- 
riation in measurements from the other strains. 
DISTRIBUTION. 
The information on distribution included herewith, as well as on 
environmental relations, dissemination, etc., was derived principally 
from special survey trips made by the writers separately during the 
summers of L921 and 1922. In addition, the Oregon State Hoard of 
Horticulture, prompted by the seeming advisability of conducting 
;m eradication campaign, made an independent survey in the summer 
